For years Google has targeted Microsoft Office with its Google Docs and Google Apps Web-based productivity suite. Office still rules the roost, but Google has been making some headway. But versions of Office being developed for the iPad and OS X Lion may help seal Microsoft's lead.

The Daily reports that Microsoft is developing a version of Office for the iPad, as well as for OS X Lion.

The version for the iPad could be a Google stopper. The Daily says it is expected to sell for somewhere around $10, the price that Apple has set for its productivity apps Pages, Numbers and Keynote. That's a remarkably low price for the suite that Microsoft charges top dollar for. Even the Home and Student version of Office, which includes Word, Excel, PowerPoint and OneNote, sells for a minimum of $99, and often more than that. As for other versions of Office, they typically sell for $300 and up.

Office is clearly superior to Google Docs, with more features, and a better-designed interface. But Google Docs is free, and is built for the Web, while Office costs a fair amount of money and is designed for client computing, so there's a temptation to choose free over quality.

At $10 for an iPad app, though, buying Office instead of using Google Docs for free on the Web becomes a no-brainer. Given the iPad's tablet dominance, it could bring in substantial revenue. Office will earn Microsoft around $15 billion in 2011. An iPad version will balloon that revenue next year.

Office's weak spot is online syncing; it doesn't have it. In addition, the free Web-based version of Office leaves a great deal to be desired. But one would expect that Office on the iPad will work with iCloud. So a Mac user could sync work from an iPad to the cloud, and then work on it on the Office version being released for OS X Lion.

Google Docs and Google Apps already lag behind Office. The new versions of Office for Mac devices will help keep them that way.